Field of the Invention
The present invention relates to an oscillatory wave motor that drives a friction member by causing a vibrator that is pressed to generate elliptical movement.
Description of the Related Art
Oscillatory wave motors are configured in such a manner that a contact portion where a flexible member is fixed and a friction member are in a pressed contact state. When under the pressed contact state, a two-phase voltage is applied to the piezoelectric element and a two-phase vibration is generated, elliptical vibration is generated at the contact portion of the elastic member and the friction member is displaced relative to the elastic member. To follow the elliptical vibration stably, a predetermined amount of flexibility is needed between the contact portion and the friction member. Japanese Patent Application Laid-Open No. 2011-234608 discloses an oscillatory wave motor configured to include a thin connecting portion having a flexibility around the contact portion which is thick.
However, the oscillatory wave motor disclosed in Japanese Patent Application Laid-Open No. 2011-234608 is significantly influenced by variation during manufacturing of the elastic member so that there is possibility that stable motor performance may not be obtained.
In the oscillatory wave motor disclosed in Japanese Patent Application Laid-Open No. 2011-234608, flexibility is imparted by only deformation of the connecting portion which is thin and provided around the contact portion. Since only the connecting portion having the thin thickness is locally deformed, the connecting portion has high sensitiveness to change in flexibility with respect to change in dimension.
Therefore, depending on dimensional variation of the connecting portion, there is possibility that the flexibility may be changed significantly and stable motor performance cannot be obtained.